he 53-year-old chief executive officer of a Boston-area corporation has agreed to testify about his alleged abuse at the hands of the Rev. Paul R. Shanley 37 years ago, charging that no one from the Archdiocese of Boston questioned him about it after he told a priest.

The man is identified in court papers as ''John Doe.'' But lawyers for alleged abuse victims said he heads a well-known company and has come forward because he was angered that Shanley had twice invoked the name of God in denying that the alleged molestation took place at Shanley's cabin in the Blue Hills in the summer of 1966.

''The letter [written by Shanley] says that the accusations which I made were unfounded,'' the alleged victim wrote in a sworn affidavit filed in Suffolk Superior Court yesterday afternoon. ''That is not true. Fr. Shanley sexually molested me.''

The businessman's testimony is important, plaintiffs' lawyers said, because it provides compelling evidence for the first time that church officials ignored allegations against Shanley as early as 1966 -- 27 years before he was removed from parish ministry.

The executive's allegations are the centerpiece of a 196-page motion filed yesterday by lawyers for Gregory Ford, a Newton man suing the archdiocese for abuse he allegedly suffered by Shanley in the 1980s.

Shanley is not a defendant in the suit, but is awaiting trial in Middlesex Superior Court on charges that he raped four boys, including Ford, while working at a now-defunct parish in Newton.

Lawyers for victims say this latest court filing is their most comprehensive compilation to date of the archdiocese's efforts to cover up sexual abuse by priests. It details allegations from numerous alleged victims of Shanley, as well as 25 other priests.

The allegations include charges that Shanley paid teenagers for sex after they were sent to him by other men.

The motion filed yesterday asks Superior Court Judge Constance M. Sweeney to allow plaintiffs, if the lawsuits go to trial, to introduce evidence that the archdiocese had ''policies and practices'' that covered up for sexually abusive priests.

Such evidence, the plaintiffs argue, refutes assertions by attorneys for the archdiocese that poor record keeping and communication among church officials -- rather than a deliberate policy -- were to blame.

Lawyers for the archdiocese have opposed the plaintiffs' bid to introduce evidence that could show a pervasive pattern of ignoring abuse. More than 500 alleged victims of clergy sexual abuse have filed civil claims against the archdiocese.

The court motion was filed as the attorney general's office is poised to release its own comprehensive accounting of the church's conduct during the sexual abuse scandal. The report, expected this week, is the result of a 16-month grand jury investigation.

According to the businessman's affidavit, he was molested by Shanley when the priest served at St. Patrick's Parish and elementary school in Stoneham in the 1960s. During the summer of 1966, the affidavit states, he was summoned to the rectory by Shanley, who told him about what he called the ''theory of the lesser of two evils.''

''He said I should consider spending the night with him there and if I felt the need to seek out sexual relief from girls, I should contact him and that the lesser of two evils would be for him to masturbate me and for me to masturbate him,'' the alleged victim, who was 16 at the time, said in his affidavit. ''He said he had put himself at risk and would take responsibility for that, in order to `save my soul.' ''

In late summer in 1966, according to the affidavit, Shanley drove him to a cabin in the Blue Hills and performed a sex act on him that night. Shanley later suggested they go to the cabin again, but the boy refused. He told his parents about the encounter the next week, according to the affidavit.

His parents took him to the Shrine of Our Lady of La Salette in Attleboro, where some of their relatives worshiped, and spoke to the Rev. Raoul Chabot. Chabot took down the boy's story, according to the affidavit, and ''told me not to worry about things and that he had friends in the Chancery and that he would take care of the matter.''

Documents from the archdiocese previously filed in court show that Chabot shared the allegations with the archdiocese. Shanley wrote a letter in his own defense, suggesting that the family was troubled and insisting ''God as my judge that I did not masturbate this boy here or anywhere else at the date or any other date, so help me God.''

The case was reviewed by Monsignor Francis Sexton, who, without interviewing the alleged victim, closed the matter by writing ''accepted as true'' on Shanley's denial letter.

Jeffrey Newman, a lawyer for the Boston firm Greenberg Traurig, which represents Ford and more than 250 other people suing the archdiocese, said the businessman has never wanted to sue the archdiocese himself. But he agreed to become a witness for other victims after the lawyers showed him Shanley's letter denying the alleged molestation in the cabin. ''It angered him so much that it pushed him over the edge,'' Newman said.

Although the businessman is remaining anonymous for now, Newman said, he has given his name to attorneys for both sides and has agreed to come forward publicly if he is called to testify as a witness.

There are currently no trial dates for either the civil cases against Shanley or his criminal trial. Lawyers for both sides have been negotiating a possible settlement of the cases and are expected to meet with Sweeney next month, after the July 30 installation of the archbishop-designate, Bishop Sean Patrick O'Malley.